Look at Paul's abc example above. There he shows how If ... Then statements on one line don't need the close End If
You might consider:
Dim arrBookmarks() As String
Dim lngIndex As Long
arrBookmarks = Split("Kapitel_EKP_Lantbruk1,A,Kapitel_EKP_Lantbruk2,Rutin_Eldning_i_det_fria,Rutin_Elinstallationer," _
& "Rutin_Gödningsmedel,Rutin_Heta_Arbeten_Lantbruk,Rutin_Hästskoning,Rutin_Högtryckstvättning," _
& "Rutin_Inomgårdsutrustning,Rutin_Insatsplan,Rutin_Lagring,Rutin_Motordrivna_fordon," _
& "Rutin_Släckutrustning,Rutin_Torkfläktar,Rutin_Uppvärmning,Rutin_Utrymning", ",")
For lngIndex = 0 To UBound(arrBookmarks)
If ThisDocument.Bookmarks.Exists(arrBookmarks(lngIndex)) Then
UserForm1.OB_Verksamhet_Lantbruk.Visible = True
Exit For
End If
Next lngIndex